1. Technical Field of the Invention
The present invention relates to a kitchenware, especially to a cooking utensil having a metallic non-stick coating.
2. Description of Prior Art
At present, a majority of non-stick cooking utensils available in market are provided with a non-stick external coating of fluoropolymer resins or similar non-metallic materials, which normally begins to deteriorate after being used for about six months. Therefore, such non-stick cooking utensils always have a short lifespan, which is a consequence of the following properties.
1. Coatings of non-metallic materials like fluoropolymer resins have a low bonding strength with the substrate of cooking utensils. If a coated cooking utensil is impacted with a small external force, the non-metallic coatings could often be damaged. Thus, a conventional non-stick cooking utensil with such coatings is usually equipped with a special accessory, which protects the cooking utensil from the impact of an external force, so as to extend its lifespan.
2. Normally, coatings of non-metallic materials like fluoropolymer resins can only bear a temperature up to about 260° C. However, it is generally required, especially by Chinese people, that a cooking be performed at a temperature higher than 260° C. Thus, the non-metallic coatings fail to be satisfactory in most cases. Moreover, when the cooking is preformed at a temperature over 300° C., the fluoropolymer resins may be decomposed, emitting a fluorine-containing gas harmful to human beings.
3. Coatings of non-metallic materials like fluoropolymer resins have a poor abrasion resistance, and are often significantly damaged after being used for a short period of time. The damage is even more serious if stuff with a hard shell such as testaceans is cooked. For most of Chinese restaurants, the cooking with a wok requires a very high temperature, but the rim portion of the wok often undergoes a “null-heating”, in which a portion of the wok is being heated without any cooking stuff on it, and therefore is always kept at a high temperature. However, current fluoropolymer non-stick cooking utensils only have a poor heat resistance. Moreover, the wok is one of the most frequently used cooking utensils in Chinese restaurants, and therefore it is highly required that the wok have a good resistance to impact and abrasion. But current fluoropolymer non-stick cooking utensils have poor performances in these two aspects, and therefore have a short lifespan. As a result, many restaurants still employ conventional iron woks without non-stick coatings, which cause a lot of inconvenience during cooking operation.
Accordingly, it is highly needed to develop a cooking utensil with a metallic non-stick coating, which has excellent impact, heat and abrasion resistances.